For the past 24 years this Core has provided researchers within this Program Project with a wide variety of well characterized cultured cells from both vascular and non-vascular sources. The personnel within this core have worked closely with researchers to develop new cell culture systems as needed to facilitate the scientific goals of the Program. In the last project period, this has included, for example, further development of methodologies for the isolation of murine lung and heart endothelium, as well as isolation of purified T cell subsets (CD8+ Tc1 and Tc2; CD4+ Th1 and Th2 cells) by immunobeads, which formed the basis of in vivo and in vitro models developed in other subprojects. Core Unit A will continue in its efforts to minimize cost duplication in this Program Project and to provide quality control testing of all key biological reagents used in tissue cultures. These products include fetal bovine serum, endothelial cell growth factors, matrix proteins such as attachment factors and enzymes. All products are routinely tested for their efficacy by core personnel, and then a price quotation is negotiated with three major suppliers, and purchased in bulk quantities for use by the program researchers. This plan has been in place for the past 15 years and has insured that cell cultures derived within this core are maintained in a consistent manner from their initial isolation from tissues through to their experimental use by the Program Project investigators. The core will continue to provide training in general cell culture methodologies and sterile technique to new program personnel (e.g., technicians, medical and graduate students, research fellows), as well as train personnel in techniques and procedures necessary for the safe handling, decontamination and disposal of biohazardous materials as well as propagation and isolation of adenovirus recombinant vectors. Core A will continue to undertake the maintenance of embryonic stem cell lines and additional cell culture materials that are required for gene targeting in mice as during the previous 10 years.